gpt 5.6 sol pro vs claude fable 5 vs grok 4.5 vs glm 5.2

today @OpenAI released the gpt-5.6 family – sol (flagship), terra, luna. key facts:

• sol is the new flagship, priced $5/m input and $30/m output

• openai claims "more work per token" and sota coding: artificial analysis coding agent index 80, browsecomp 92.2%, osworld 2.0 62.6%

• sol pro = the highest-quality chat tier for complex tasks; the family also ships an 'ultra' setting that runs 4 agents in parallel

• we ran sol pro

our test – 3 prompts, single-file html, three.js:

1. floating-island district of london – tower bridge, big ben, london eye, the shard, tower of london

2. floating-island district of paris – pont alexandre iii, eiffel, arc de triomphe, louvre, notre-dame

3. floating-island district of nyc – brooklyn bridge, empire state, chrysler, one wtc, flatiron, statue of liberty

requirements: two square floating islands, sheer cliffs, waterfalls pouring only from drainage pipes (real stream geo, foam, spray, mist), fps fly-cam, every square meter packed with landmarks + city fabric, cinematic golden-hour sky, bloom, no ui, no text

results (summed across all 3 cities):

cost
#1 grok 4.5 – $0.41
#2 glm 5.2 – $1.45
#3 gpt 5.6 sol pro – $4.12
#4 fable 5 – $11.37

tokens
#1 grok 4.5 – 60,291
#2 fable 5 – 174,083
#3 gpt 5.6 sol pro – 241,739
#4 glm 5.2 – 243,188

lines of code
#1 fable 5 – 2,830
#2 gpt 5.6 sol pro – 3,003
#3 glm 5.2 – 3,474
#4 grok 4.5 – 3,830

sol pro's code quality – reviewed by opus 4.8:

upsides:

- modern r164 stack, zero deprecated apis, correct color management via outputpass

- instancedmesh batches thousands of skyscraper windows into single draw calls

- every cliff and facade is a procedural canvas texture, no external assets

- clean animate loop, no per-frame allocations

downsides:

- the glass reflects nothing – materials set envmapintensity 1.3–1.4 and transmission, but no scene.environment or envmap is ever created, so the spec's "reflections on glass" don't exist

- the city has no instancing or merging: box() mints a fresh geometry per call and every window is its own plane mesh, so london and paris ship thousands of draw calls with instancedmesh count 0

- one 2048² shadow map is stretched across the whole 440-unit district, so shadows come out coarse and crawling. and ~58% of buildings get a random cone "pyramid" roof regardless of style while ~32% skip casting shadows outright

pattern: it writes a clean, deprecation-free scene that photographs well – then skips the reflections, draw-call discipline and material depth the prompt asked for. built for the thumbnail, not the spec

observations:

• all four are mid – frontier "graphics" aren't best-of-the-best. prettiest is london by glm 5.2, still not ideal

• bridges break everyone: fable joins two towers with chains, no roadway. sol pro opens its bascule down instead of up

• sol pro floats cars with no road in nyc

• sol pro trends toward simple, boxy shapes – fable too

models that were "5 minutes to agi" now ship sloppy and perform at roughly glm 5.2 level. glm is closing the gap from below, and political decisions are closing it from our side